Landlord cashed cheque from government rent support and said he didn’t receive it

A legal question as a tenant in Alberta, Canada:

Over Covid my fiancé qualified for some rent support. They sent three supplement cheques directly to our landlord. He said he only received two, but we contacted the organization and they confirmed that three were sent and they were all cashed. Two were cashed on the same day and one a few weeks later, all in June. The landlord is refusing to believe this, despite us forwarding emails from the organization stating that they’ve given us as much information as they can due to confidentiality, we’ve asked him to check his bank statements.

Just wondering legally what ground we have to stand on. In my mind it is up to him to prove, at this point, that he didn’t receive these, since it seems logical that if he cashed two of them, the third was also cashed.

We asked him to look into it again and are awaiting a response, we’ve given him the dates that the cheque’s were cashed to assist with narrowing down the day.

What course of action should we take if he continues to say he doesn’t remember cashing it or didn’t receive it? I’m considering deducting this missing cheque from my upcoming rent and giving him the contact information of the government organization if he claims he didn’t get it.